#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
char* my_strcat(char* dev,char* src)
{
	char* ret = dev;
	while (*dev != '\0')
	{
		dev++;
	}
	while (*dev++ = *src++);
	return ret;
}
int main()
{
	char arr[] = { "ABCD" };
	char arr2[20] = { "abcd" };
	char* p =my_strcat(arr2, arr);
	for (int i = 0; i < 8; i++)
	{
		printf("%c ", *(p + i));
	}
	return 0;
}